I recommend checking out the tahiti-explorer.com forums for more information:
http://www.tahiti-explorer.com/cgibi...ultimatebb.cgi They have a ton of threads on exchange rates and ideas on how to get the best bang for your buck. Also, they have many posts on all of the properties.
My wife and I stayed in Sheraton Moorea and BBN for our honeymoon last September and it was one of the best trips I have ever taken in my life. Both islands and resorts were amazing! Sheraton Moorea had better snorkeling right off of the property and also had tennis courts (a big plus for us...) while the BBN was a lot more secluded and luxurious. I agree with mmichele - go to Moorea first and then Bora Bora.
By the way, if you book through one of the package vendors, like tahiti-explorer.com, they are able to get the BBN over water bungalow for about $700/night (still gives your points and stay credit).